This invention relates to obtaining, noninvasively, image information about an object, e.g., three-dimensional information about a vascular tree within a living body.
In classic X-ray imaging, X-rays projected through the body expose a film to form a two-dimensional image.
More recent computerized X-ray tomography techniques provide two-dimensional images (tomograms) of cross-sectional slices through the body. Nuclear magnetic resonance (NMR) has also been used to create tomograms.
One way to obtain three-dimensional information is to acquire data for a succession of tomograms associated with a stack of cross-sectional slices.
Typically, in NMR, the amount of time required to acquire the image information generally depends on the number of picture elements (pixels) desired in the final image. For three-dimensional information, the total time is typically a large multiple of the time for a single two-dimensional tomogram.
Two-dimensional NMR images (both tomographic and projective) of a vascular tree can be enhanced by taking advantage of the contrast between the motion of the blood within the vessels and the general lack of motion of the surrounding tissue.
It has been proposed to obtain three-dimensional information about a vascular tree by acquiring a succession of two-dimensional NMR tomograms and interpolating between them to obtain the three-dimensional information. Typically the resolution within the plane of each tomogram is one mm, while the resolution from tomogram to tomogram is only five to ten mm.